CN101316074B - Back-to-back three-power level midpoint clamping current transformer of wind power generation system - Google Patents

Back-to-back three-power level midpoint clamping current transformer of wind power generation system Download PDF

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CN101316074B
CN101316074B CN2008101027538A CN200810102753A CN101316074B CN 101316074 B CN101316074 B CN 101316074B CN 2008101027538 A CN2008101027538 A CN 2008101027538A CN 200810102753 A CN200810102753 A CN 200810102753A CN 101316074 B CN101316074 B CN 101316074B
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switching tube
anode
diode
negative electrode
rectifier
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CN101316074A (en
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许洪华
李建林
朱颖
赵斌
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Institute of Electrical Engineering of CAS
Beijing Corona Science and Technology Co Ltd
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Institute of Electrical Engineering of CAS
Beijing Corona Science and Technology Co Ltd
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/70Wind energy
    • Y02E10/76Power conversion electric or electronic aspects

Abstract

The invention provides a back-to-back three-level midpoint clamp converter in a wind generation system, comprising a rectifier beside a motor and an inverter beside the network; an AC input terminal is connected with a stator side output terminal of a permanent magnetic synchronous generator; the output terminal of the inverter is connected with an electricity grid. The output of the rectifier is connected with the input of the inverter; the midpoints of the rectifier and the inverter behind a diode clamp are connected with each other; the rectifier and the inverter require the control of a digital signal processing chip DSP. The back-to-back three-level midpoint clamp converter utilizes the three-level rectifier and the inverter of the midpoint clamp in the diode, increases the capacity of the wind generation system by a space vector controlling method, and obviously improving the shape of the voltage waveform output to the electricity grid so as to be adapt to the standard of the parallel electricity grid more excellently.

Description

The three level neutral point clamp current transformers back-to-back of wind generator system
Technical field
The present invention relates to the three level neutral point clamp current transformers back-to-back in the wind generator system.
Background technology
In recent years, many level current transformers have been subjected to the common concern of Chinese scholars in high pressure, high-power field.The thought of many level current transformers was proposed by people such as Nablae early than 1981, and its basic ideas are to approach sinusoidal output voltage by the synthetic staircase waveform of several level steps.Many level current transformers are as a kind of novel high-voltage large-capacity power converter, start with from circuit topological structure, when obtaining the high-quality output waveform, many shortcomings of two level current transformers have been overcome, need not output transformer and dynamic voltage-balancing, switching frequency is low, and has switching device stress little, series of advantages such as system effectiveness height.
Along with the rising of switching device capacity, the improvement of switch conduction characteristic, the advantage of many level current transformers is more and more significant.Its advantage is mainly reflected in and reduces the input and output harmonic wave, has reduced the volume and the capacity of input filter, reduces electromagnetic interference (EMI).Relative two level current transformers, many level current transformers switching frequency has reduced by 25%, therefore can reduce switching loss.The major defect of many level current transformers is the equilibrium problem of direct voltage.At this problem, the solution of hardware and software is arranged.The hardware method needs extra switching tube, increases the cost of system and reduces stability, and the software method need be controlled modulation signal has increased computation burden.To all pressures problem of many level, the solution of the existing comparative maturity of various countries scholar.
The trend in wind energy conversion system market is that rated capacity, electric current and voltage grade improve constantly.And traditional current transformer is because the restriction of electric current and voltage capacity can not directly apply to big capacity wind generator system.Such as United States Patent (USP) 7,239,535, it is the voltage current transformer of common 6 power switch pipes of two level, its control method is also just carried out complementary conducting to two switching tubes of its every phase brachium pontis, and promptly two switching tubes take turns conducting up and down, and the phase voltage of output has only two kinds of level of height.From its accompanying drawing 5 as can be seen, the current waveform sawtooth of its output is a lot, second-rate.Therefore also limited its current/voltage capacity.So the plurality of advantages of many level current transformers makes it be well suited for being applied to novel wind energy conversion system.Along with the increase of electric pressure, many level current transformers can directly insert distributed power grid, save heavy step-up transformer.
The thought of many level current transformers proposes so far, many circuit topologies occurred, concluded and get up to mainly contain following three kinds: the many level current transformers of diode-clamped (diode-clamped multi-level converter), the many level current transformers of Cascade H bridge type (cascade Hbridge multi-level converter) and the many level current transformers of striding capacitance type (flying-capacitor multi-level converter).In these three kinds of topological structures, diode reed position three-level current transformer is because it has multipleization and pulse-width modulation simultaneously, and it is big to have power output, and the devices switch frequency is low, the equivalent switching frequency height; AC side does not need transformer to connect, and dynamic response is good, and advantages such as transmission bandwidth broad are most widely used in the mesohigh large-power occasions.
Summary of the invention
The objective of the invention is to overcome the existing high shortcoming of current transformer capacity low harmonic content, propose a kind of new converter topologies and control method.The present invention can improve the electric current and voltage capacity of current transformer significantly, and improves the shape of output waveform significantly, to adapt to the standard that electrical network is incorporated into the power networks better.
The present invention adopts power diode to form " many level " function as clamping device.With respect to two traditional level current transformers, major advantage of the present invention is: the voltage stress that individual devices bears is little, easier realization high-power; Under the same switch frequency, the more approaching sine wave of output waveform, harmonic content is lower; Also alleviated the electromagnetic interference (EMI) problem simultaneously greatly.
The present invention's wind generator system at current transformer place, three level mid point reed positions back-to-back is made of wind-powered electricity generation unit, generator, generator side converter, dc bus capacitor, DC side-discharging circuit, grid side current transformer, grid side filter inductance and electrical network.
Dragging wind-driven generator by the wind-powered electricity generation unit, is the wind energy transformation of catching electric energy, is converted into direct current by the generator side converter, dc bus capacitor is as the energy snubber link, stable DC side voltage is dc inverter alternating current by the grid side current transformer, is connected to the grid by filter inductance.
The present invention's three level neutral point clamp current transformers back-to-back comprises the rectifier of blower fan side and the inverter of grid side, the principle of their topological structure is identical, rectifier is responsible for alternating current is converted to direct current in the blower fan side, inverter is responsible for direct current is converted to alternating current in grid side, because the present invention's topological structure of three level neutral point clamp current transformers back-to-back allows the energy two-way flow, if so the input and output of rectifier are changed, just become inverter, vice versa.The present invention's three level neutral point clamp current transformers has back-to-back incorporated the electric capacity of pair of series in the dc bus junction of rectifier and inverter, mid-point voltage and buffering energy are provided.
The present invention adopts the core of digital signal processing chip DSP as controller, and DSP can realize the real-time processing to sampled signal, and sends control signal corresponding according to the control needs.Realize among the present invention space vector modulation by it to motor side rectifier and net side inverter.Peripheral circuit comprises sample circuit and signal conditioning circuit.Sample circuit is gathered three phase network voltage, electric current and the alternating current of each current transformer, the direct voltage at electric capacity two ends etc. by voltage, current sensor, and sending into signal conditioning circuit carries out signal condition, sends into the AD sampling channel of DSP then.DSP calculates the required conducting of each switch, after the turn-off time, PWM mouth by DSP sends the needed switching signal of control each switch of current transformer, after amplifying, isolate, overdrive circuit is connected on the driving gate pole of each power device, thus control motor side rectifier and net side inverter operate as normal.
The course of work of the present invention is as follows:
Below rated wind speed, propeller pitch angle is constant substantially to keep the power coefficient maximum.Wind generator system obtains the maximum power that system is input to electrical network according to the maximum power algorithm, obtains the optimum speed of generator thus, makes the power output maximum of system by the active current of regulating combining inverter, and motor operates in optimum speed.
On rated wind speed, keep the power coefficient maximum by becoming oar.Motor and current transformer all operate under the rated condition, and system outputs to the power maximum of electrical network.
When wind speed surpassed cut-out wind speed, system-down, the power that outputs to electrical network were zero.
Rectifier in the back-to-back converter can regulator generator the reactive power of output, effectively regulate the motor output power factor, when the needs motor is output as unity power factor, make that reactive current is zero, can make motor export maximum active power like this.Simultaneously, because idle output is adjustable, make the generator speed scope wideer.The all right stable DC side voltage of motor side rectifier provides the galvanic current source to combining inverter.The net side inverter is responsible for reconciling active power and the reactive power that wind generator system is input to electrical network, and when electrical network needs in advance when idle, the setting reactive current is a negative value; When electrical network need lag behind when idle, set reactive current and be on the occasion of; When needs are input to the active power maximum of electrical network, when reactive power was zero, can set reactive current was zero, and net side power factor is 1.It more than is the operating state of the present direct-drive wind power system of using always.
The present invention is by 27 kinds of on off state combinations of 12 power switch pipes, every phase brachium pontis input produces 3 kinds of level, a plurality of diode pair respective switch elements carry out clamp, to guarantee that every next brachium pontis has only a switch motion, and realize the output of three level, and each switching device only bears 1/2 DC bus-bar voltage, has both realized that the AC side power factor is adjustable, reduce irregularity of wave form, also can realize powerful transmission.
Description of drawings
Fig. 1 direct-drive wind power system schematic diagram;
Fig. 2 is three level neutral point clamp converter topologies figure back-to-back;
Fig. 3 inverter one facies principle figure;
Fig. 4 inverter one is three level generating principle figure mutually;
Fig. 5 back-to-back converter control block diagram.
Embodiment
Further specify the present invention below in conjunction with the drawings and specific embodiments.
As shown in Figure 1, the direct-drive aerogenerator group comprises wind-powered electricity generation unit, generator, blower fan side rectifier, dc bus capacitor, DC side-discharging circuit, grid side inverter, grid side filter inductance and electrical network.The present invention's three level neutral point clamp current transformers back-to-back comprises the inverter of blower fan side rectifier and grid side.The stator three-phase wire of wind turbine generator is connected respectively between switching tube S2 and the S3, between S6 and the S7, between S10 and the S11.The output of rectifier and the input of inverter are connected in an A and put B, as shown in Figure 2.The same with the input of rectifier, the output of inverter is received electrical network G through after the inductance L.
Fig. 2 is the present invention's three level neutral point clamp converter topologies back-to-back.
The present invention's three level neutral point clamp current transformers back-to-back comprises the rectifier of blower fan side and the inverter of grid side, the principle of their topological structure is identical, being the input and output transposing back work of rectifier of pusher side of keeping watch at the inverter of grid side only, also is back-to-back so-called.As shown in Figure 2, the inverter of the rectifier of blower fan side and grid side is made up of switching tube and power diode.Every four switching tubes, three-phase altogether of comprising mutually.Each switching tube all inverse parallel a power diode, so that reverse-conducting to be provided.Its concrete connected mode is every phase four switching tube S1~S4, S5~S8, S9~S12 series connection.With switching tube S1, S2, S3 and one of S4 series connection is example mutually, the anode of switching tube S1 is connected to dc bus A, the negative electrode of switching tube S1 connects the anode of S2, the anode of switching tube S2 connects the input of wind-driven generator one cross streams electric wire and the anode of switching tube S3, the negative electrode of switching tube S3 connects the anode of switching tube S4, and the negative electrode of switching tube S4 connects dc bus B.What connect between switching tube S1 and S2 is the negative electrode of diode D1, and the anode of diode D1 is connected to the negative electrode of mid point point position bus C and diode D2, and the anode of diode D2 is connected between switching tube S3 and the S4.Second is switching tube S5, S6, S7 and S8 series connection mutually, the anode of switching tube S5 is connected to dc bus A, the negative electrode of switching tube S5 connects the anode of S6, the anode of switching tube S6 connects the input of wind-driven generator one cross streams electric wire and the anode of switching tube S7, the negative electrode of switching tube S7 connects the anode of switching tube S8, and the negative electrode of switching tube S8 connects dc bus B; What connect between switching tube S5 and S6 is the negative electrode of diode D3, and the anode of diode D3 is connected to the negative electrode of mid point point position bus C and diode D4, and the anode of diode D4 is connected between switching tube S7 and the S8; Third phase is switching tube S9, S10, S11 and S12 series connection, the anode of switching tube S9 is connected to dc bus A, the negative electrode of switching tube S9 connects the anode of S10, the anode of switching tube S10 connects the input of wind-driven generator one cross streams electric wire and the anode of switching tube S11, the negative electrode of switching tube S11 connects the anode of switching tube S12, and the negative electrode of switching tube S12 connects dc bus B; What connect between switching tube S9 and S10 is the negative electrode of diode D5, and the anode of diode D5 is connected to the negative electrode of mid point point position bus C and diode D6, and the anode of diode D6 is connected between switching tube S11 and the S12.
The three-phase alternating current of wind-driven generator is input to the centre of every commutating phase bridge.One to be example mutually, the three-phase alternating current of wind-driven generator is input between switching tube S2 and the switching tube S3.Two dc bus A that the output of rectifier is and B, that middle is midpoint potential bus C.The input of inverter is two the dc bus A and the B of rectifier output, and its topological structure is identical with rectifier, and output is received electrical network G by series inductance L.
Between two dc bus A and B, connected two capacitor C 1 and C2, and that connect between C1 and the C2 is exactly midpoint potential bus C.
Wind generator system of the present invention is when operation, and the size according to extraneous wind speed mainly contains three kinds of operating states:
(1) when wind speed is lower than the rated wind speed of system works, propeller pitch angle is constant substantially, to keep the power coefficient maximum.System obtains the maximum power that system is input to electrical network according to the maximum power algorithm, obtains the optimum speed of generator thus, makes the power output maximum of system by the active current of regulating combining inverter, and motor operates in optimum speed.General reactive power is given as zero, makes system works at maximum active power output state, improves the efficient of system.When electrical network needs idle support, can send or absorb the reactive power of electrical network as required to electrical network.Active power and reactive power can realize independent regulation.
(2) when wind speed is higher than the rated wind speed of system, keep the power coefficient maximum by becoming oar.Motor and current transformer all operate under the rated condition, and system outputs to the power maximum of electrical network.
(3) when wind speed surpasses the cut-out wind speed of system, system-down, the power that outputs to electrical network are zero.
The on off state combination of rectifier of the present invention is as follows:
To the on off state of the switching tube of a phase, as following table, " 1 " expression is opened, and " 0 " expression is closed:
As can be seen, corresponding to 3 kinds of phase voltages, 4 switching tubes have 3 kinds of on off states respectively, so for the situation of three-phase, 12 switching tubes just have 3 3=27 kinds of on off states.
Three level of net side inverter produce:
Fig. 3 is the wherein schematic diagram of a phase of a grid side inverter, and diode D1 and D2 are used for voltage clamp, capacitor C 1 and C2 for three-level current transformer provide E/2 and-direct voltage of E/2.
In conjunction with Fig. 3 and Fig. 4, as can be seen, the operation principle of diode clamping tri-level is as follows:
(1) switching tube Q1, Q2 conducting, when Q3, Q4 turn-off: shown in Fig. 4 a, electric current I aFor flowing out direction, then capacitor C 1 is by load discharge, and electric current flows through switching tube Q1, Q2, ignores tube voltage drop, this phase output terminal voltage V Out=E/2.Shown in Fig. 4 b, electric current I aBe inflow direction, electric current flows through the fly-wheel diode in parallel with switching tube Q1, Q2 to capacitor C 1 charging, and then this phase output terminal voltage is V Out=E/2.
(2) switching tube Q2, Q3 conducting, when Q1, Q4 turn-off: shown in Fig. 4 c, electric current I aFor flowing out direction, then electric current flows through clamping diode D1, switching tube Q2, at this moment this phase output terminal voltage V Out=0, and capacitor C 2 charged.Shown in Fig. 4 d, electric current I aBe inflow direction, then electric current flows through and is responsible for Q3, flows through clamping diode D2 again, and then this phase output terminal voltage is V Out=0, and capacitor C 1 charged.
(3) switching tube Q3, Q4 conducting, when Q1, Q2 turn-off: shown in Fig. 4 e, electric current I aFor flowing out direction, then capacitor C 2 is by load discharge, and electric current flows through is responsible for Q3, Q4, this phase output terminal voltage V Out=-E/2; Shown in Fig. 4 F, electric current I aBe inflow direction, electric current flows through with switching tube Q3, Q4 diode connected in parallel D1, D2 capacitor C 2 is charged, and then this phase output terminal voltage is V Out=-E/2.
The operating state that Fig. 4 a, c, e are the current transformer electric current when DC power supply E flows out.When as Fig. 4 a and Fig. 4 c two states alternate, switching tube Q2 is in opening state, sustained diode 1, the D2 of switching tube Q1 and switching tube Q3, Q4 so, and load inductance just constituted typical B UCK circuit, this voltage of exporting mutually switches between E/2,0.When as Fig. 4 (c) and Fig. 4 (e) two states alternate, this brachium pontis still is operated in the BUCK circuit state, this phase output voltage 0 ,-switch between the E/2.
Fig. 4 b, d, f are the operating state of current transformer electric current when DC power supply E flows into.When as Fig. 4 b and Fig. 4 d two states alternate, switching tube Q3, diode D1, the D2 of switching tube Q1, Q2, and load inductance just constituted typical boost circuit, this voltage of exporting mutually switches between E/2,0.When as Fig. 4 d and Fig. 4 f two states alternate, switching tube Q3 is in opening state, and this brachium pontis still is operated in the boost circuit state, this voltage of exporting mutually 0 ,-switch between the E/2.
The control block diagram of whole wind force generating system is as shown in Figure 5: the current i of rectifier sampling motor output a, i b, i c, utilize photoelectric code disk or Speedless sensor to obtain the rotor position angle θ of motor r, the conversion of electric current process Parker obtains the dq component i of electric current dAnd i qu DcAnd u DcGiven u Dc *Carry out the PI adjusting after doing difference, be output as i qGiven i q *, i dBe given as i d *, by the motor side power factor require givenly, be generally zero, make motor active power of output maximum.i qAnd i q *Differ from i dAnd i d *Carry out adding after PI regulates the compensation term ω (L of above two differences after the work difference respectively di d+ ψ f) and-ω L qi qJust can obtain the dq component u of rectifier reference voltage dAnd u q, process Parker inverse transformation obtains the result of calculation u of three-phase voltage again u, u v, u wPass through the controlled signal of SVM algorithm at last, rectifier is at stable DC side voltage u DcThe time, realize motor output reactive current i dControl.
Inverter sampling grid side voltage u Sa, u Sb, u ScWith the current i that outputs to electrical network Sa, i Sb, i Sc, obtain active power P and the reactive power Q of actual fed to electrical network through power calculation unit.According to the maximum power algorithm, utilize active power P and motor speed ω to obtain the motor optimum speed with reference to ω *, ω *Do after the difference through PI ring with ω, obtain current transformer and be input to the active current of electrical network with reference to i Sq *, reactive current is with reference to i Sd *Generally be given as zero, allow the active power maximum of current transformer input electrical network, improve the efficient of system.Active current reference quantity i Sq *With reactive current reference quantity i Sd *After doing difference respectively with the meritorious reactive current of reality, add above two poor compensation term ω L through pi regulator Sdi dWith-ω L Sqi qObtain the Voltage Reference u of inverter Sd, u Sq, obtain u through the Parker inverse transformation again a, u b, u cJust can make inverter be operated in power factor of electric network through the PWM generator of SVPWM control at last is 1.Because active power equals voltage, electric current and power factor three's product, and power factor is always smaller or equal to 1, so, when power factor of electric network is 1, be input to the active power maximum of electrical network.
The present invention has used the clamp power diode, has structurally realized the input and output of three level.In control method, added midpoint potential u DcControl.Both combine and can well avoid existing full power convertor because the flow of power imbalance, cause the problem of the rising of the intermediate capacitance voltage in the back to back structure.

Claims (1)

1. the three level neutral point clamp current transformers back-to-back of a wind generator system comprise a motor side rectifier and a net side inverter; Described motor side rectifier is connected back-to-back with the net side inverter, i.e. the direct current input of the direct current of motor side rectifier output and net side inverter is connected; Described motor side rectifier and net side inverter all use diode to realize the stable of midpoint potential; The dc bus junction of motor side rectifier and net side inverter has been incorporated the electric capacity (C1, C2) of pair of series into, and mid-point voltage and buffering energy are provided;
In the described motor side rectifier, four switching tubes of every phase (S1~S4, S5~S8, S9~S12) series connection; First is first switching tube to the, four switching tubes (S1, S2, S3, S4) series connection mutually, the anode of first switching tube (S1) is connected to first dc bus (A), the negative electrode of first switching tube (S1) connects the anode of second switch pipe (S2), the anode of second switch pipe (S2) connects the input of wind-driven generator one cross streams electric wire and the anode of the 3rd switching tube (S3), the negative electrode of the 3rd switching tube (S3) connects the anode of the 4th switching tube (S4), and the negative electrode of the 4th switching tube (S4) connects second dc bus (B); What connect between first switching tube (S1) and second switch pipe (S2) is the negative electrode of first diode (D1), the anode of first diode (D1) is connected to the negative electrode of mid point point position bus C and second diode (D2), and the anode of second diode (D2) is connected between the 3rd switching tube (S3) and the 4th switching tube (S4); Second is the 5th switching tube to the eight switching tubes (S5, S6, S7, S8) series connection mutually, the anode of the 5th switching tube (S5) is connected to first dc bus (A), the negative electrode of the 5th switching tube (S5) connects the anode of the 6th switching tube (S6), the anode of the 6th switching tube (S6) connects the input of wind-driven generator one cross streams electric wire and the anode of the 7th switching tube (S7), the negative electrode of the 7th switching tube (S7) connects the anode of the 8th switching tube (S8), and the negative electrode of the 8th switching tube (S8) connects second dc bus (B); What connect between the 5th switching tube (S5) and the 6th switching tube (S6) is the negative electrode of the 3rd diode (D3), the anode of the 3rd diode (D3) is connected to the negative electrode of mid point point position bus C and the 4th diode (D4), and the anode of the 4th diode (D4) is connected between the 7th switching tube (S7) and the 8th switching tube (S8); Third phase is that the 9th switching tube to the twelvemo is closed pipe (S9, S10, S11, S12) series connection, the anode of the 9th switching tube (S9) is connected to first dc bus (A), the negative electrode of the 9th switching tube (S9) connects the anode of the tenth switching tube (S10), the anode of the tenth switching tube (S10) connects the input of wind-driven generator one cross streams electric wire and the anode of the 11 switching tube (S11), the negative electrode of the 11 switching tube (S11) connects the anode that twelvemo is closed pipe (S12), and the negative electrode that twelvemo is closed pipe (S12) connects second dc bus (B); What connect between the 9th switching tube (S9) and the tenth switching tube (S10) is the negative electrode of the 5th diode (D5), the anode of the 5th diode (D5) is connected to the negative electrode of mid point point position bus C and the 6th diode (D6), and the anode of the 6th diode (D6) is connected to the 11 switching tube (S11) and twelvemo is closed between the pipe (S12);
In the described net side inverter, used two diode pair respective switch pipes to carry out clamp, have only a switch motion to guarantee every next brachium pontis, and realize the output of three level, and each switching device has only born 1/2 DC bus-bar voltage; By the usage space vector modulation method, the alternating current of output is three level; Suppose that its DC input voitage is E, then the alternating current of output form be divided into E/2,0 ,-three level of E/2, it is characterized in that, described current transformer to the control procedure of described wind generator system is: when wind speed is lower than the rated wind speed of described wind generator system work, the propeller pitch angle of wind generator system is constant substantially, to keep the power coefficient maximum; Wind generator system obtains the maximum power that system is input to electrical network according to the maximum power algorithm, obtain the optimum speed of generator thus, make the power output maximum of described wind generator system by the active current of regulating the motor side inverter, motor operates in optimum speed; When wind speed is higher than the rated wind speed of described wind generator system, keep the power coefficient maximum by regulating described propeller pitch angle;
Described current transformer is as follows to the process of described wind generator system control: the current i of described motor side rectifier sampling motor output a, i b, i c, utilize photoelectric code disk or Speedless sensor to obtain the rotor position angle θ of motor r, the conversion of electric current process Parker obtains the dq component i of electric current dAnd i qStable DC side voltage u DcAnd u DcGiven Carry out the PI adjusting after doing difference, be output as i qGiven i dBe given as By the motor side power factor require givenly, be generally zero, make motor active power of output maximum; The dq component i of electric current dWith poor, i dWith the compensation term ω (L that carries out adding after PI regulates above two differences after the work difference respectively di d+ ψ f) and-ω L qi qJust can obtain the dq component u of described rectifier reference voltage dAnd u q, process Parker inverse transformation obtains the result of calculation u of three-phase voltage again u, u v, u wPass through the controlled signal of space vector algorithm at last, make described rectifier at stable DC side voltage u DcThe time, realize the control of motor output reactive current id.
CN2008101027538A 2008-03-26 2008-03-26 Back-to-back three-power level midpoint clamping current transformer of wind power generation system Active CN101316074B (en)

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CN105375849A (en) * 2015-11-25 2016-03-02 北京金自天正智能控制股份有限公司 Three-level circuit board for realizing permanent magnet synchronous motor variable-frequency soft start and grid-connected control
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CN108418415B (en) * 2018-03-08 2020-04-03 浙江大学 Three-phase four-wire zero-voltage switch back-to-back converter circuit and modulation method thereof
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